@hazardwarning A desktop PC can easily last 10 years. A laptop considerably less but the marginal cost to support laptops is minimal. The infrastructure around a PC changes fairly slowly so you can still use those older PCs even today (trust me, I have a lot of older PCs at home).
Mobile devices do not, by and large, last that long. The most you can get out of a battery is 2 years, if that. The battery isn't easy to replace in some of these devices. The cost to repair these devices (particularly the cheap Android ones) is worth more than simply replacing the device. Even though I still have a Nokia N95 from 2007, the other technology it relies on has progressed so much that I can use it for little more than calls, texts, and taking pictures. Once the local providers switch off 2G, I won't even be able to use it for calls.
In short, I don't think a 10 year lifecycle for mobile devices is practical, at least right now. Things are evolving way too fast for that to make economic sense.
// @matigo